Gusting Santa Ana winds fueled brush fires Wednesday, including a 600-acre blaze in a largely uninhabited area near Tecate that sent smoke over parts of San Diego County and caused ash to fall in Chula Vista, National City and Imperial Beach.

Update

Cal Fire officials said Thursday that while they continue to monitor the fire burning in Tecate its threat has diminished because the winds have died down. The fire has not crossed into the United States.

Cal Fire stationed crews at the Otay Mesa Port of Entry in case the fire spread across the border from Mexico and were ready to help Mexican firefighters if needed. Fire officials in Mexico asked for Cal Fire’s assistance in the afternoon but later canceled the request.

The fire was still burning at sundown, with Mexican fire officials not saying when it would be contained.

Firefighters in San Diego County, meanwhile, managed to contain two small brush fires. The largest burned 12 acres in the Black Mountain Ranch area at the northern reaches of San Diego. The city’s firefighters kept it from reaching homes that were about a half mile away.

Cal Fire responded to two small blazes in the county, one a rubbish fire in Dulzura and the other a one-acre brush fire near Harrah’s Rincon casino in Valley Center.

“We dodged a bullet,” Cal Fire Capt. Michael Mohler said, given the winds and low humidity. He said crews were on high alert, and Cal Fire will retain extra staffing Thursday.

A red-flag warning issued by the National Weather Service was in effect until 9 p.m. Wednesday in the county. The warnings are made when sustained winds of at least 25 mph or frequent gusts of 35 mph occur, combined with 15 percent or lower humidity over at least six hours.

Wind gusts as high as 50 mph were reported Wednesday in parts of East and North County. Winds were expected to diminish overnight. Light rain is forecast Thursday night and Friday, with up to a quarter-inch possible along the coast and a half-inch in the valleys and foothills.

The National Weather Service said the snow level may drop to 3,500 feet, with light snow possible atop Palomar Mountain.

Tecate fire

On Wednesday, South County residents said smoke from the fire in Mexico was thick at times, and some reported eye and throat irritation and difficulty breathing. By early evening, residents as far north as La Jolla reported smelling smoke.

Imperial Beach resident Chris Morrow, who lives near the Tijuana Estuary, closed all of her condo windows and kept her two dogs inside. She went outside to take some video of the fire, but said it was “difficult to breathe.” She said some people outside were holding cloths over their faces.

The fire in Mexico began shortly after 10 a.m. about two miles south of the border in the area of Valle Redondo, south of the toll road between Tijuana and Tecate, said Carlos Carreno, spokesman for the Tijuana Fire Department.

Alfredo Escobedo, Baja California’s civil protection chief, said firefighters were trying to protect some rural cabins. The mountainous area is difficult to access, he said.